Egg Facts

What is the difference between brown and white eggs?

Shell colour varies with the breed of hen and is not related to quality, nutrients, flavour or cooking characteristics. The breed of hen determines the colour of the shell. Hens with white feathers and ear lobes lay white eggs; hens with red feathers and ear lobes lay brown eggs. There is no difference in quality, flavour, or nutritional value of the egg.

Why do egg yolks differ in colour?

Yolk colour depends solely on the diet of the hen as artificial additives to enhance yolk colour are not permitted. If a hen gets plenty of yellow-orange plant pigments (xanthophylls), these will be deposited into the yolk. Hens fed food containing yellow corn lay eggs with medium yellow yolks. Those eating wheat or barley lay lighter-colour yolks. Colour variations have no effect on the quality, flavour or nutritional value of the egg.

How many eggs can I eat?

Eggs are a highly nutritious food that can make an important contribution to a healthy, well balanced diet. They are a natural source of at least 11 different vitamins and minerals as well as high quality protein, omega-3 fats and antioxidants. The New Zealand Nutrition Foundation suggests eating up to six eggs a week as part of a healthy, balanced diet.

How long do eggs last?

The best before date on a carton of eggs tells you how long the eggs inside it stay ‘fresh’ if they are kept refrigerated after purchase. During this time (usually about 35 days) there is little change in the nutritional value of the egg, but the appearance and qualities of the egg may change as the egg ages. Poached or fried eggs hold their shape better the fresher the egg, but hard boiled eggs are much easier to peel if the eggs are at least one week old.

Temperature, humidity and handling all contribute to freshness. A one week old egg kept in ideal conditions can be fresher than an egg left at room temperature for one day. Most commercially produced eggs reach supermarkets within a few days of being laid and in New Zealand it is also possible to purchase eggs which are guaranteed to be sold the same day they are laid.

How can I tell if an egg is still fresh?

A quick test for freshness is to check if the raw egg in the shell sinks in a basin of water. Fresh eggs stay at the bottom of the bowl while older eggs float because of the large air cell that forms in its base.

How do I check whether an egg is boiled or raw?

To tell if an egg is raw or hard-boiled, spin it, if the egg spins easily, it is hard-boiled but if it wobbles, it is raw.

I’ve had a carton of eggs in my fridge for a few weeks. Can I still use them?

You can use your oldest eggs for baking cakes, quiches and frittatas. Older eggs can also be useful for hard-boiling, scrambling, and making omelettes. If hard-boiling, it is best to use eggs a few days old. The fresher the egg, the more likely the white will stick to the shell.

How safe are eggs?

The risk of getting an illness from eggs is very low. However, the nutrients that make eggs a high-quality food for humans are also a good growth medium for bacteria. In addition to food, bacteria also need moisture, a favourable temperature and time in order to multiply and increase the risk of illness. In the rare event that an egg contains bacteria, you can reduce the risk by proper chilling and eliminate it by proper cooking. When you handle eggs with care, they pose no greater food-safety risk than any other perishable food.

Is it safe to eat raw eggs?

It’s best not to serve raw or lightly cooked dishes made with eggs. The risk of food poisoning from eggs is highest with raw and lightly cooked dishes.

What causes blood spots?

Small spots of blood are occasionally found in an egg yolk. These do not indicate a fertile egg; they are caused by the rupture of a blood vessel on the yolk surface during formation of the egg. Such eggs are suitable for consumption and the spot can be easily removed with the tip of a knife.

Why are some hard-cooked eggs difficult to peel?

Cooked fresh eggs can be difficult to peel. Eggs that are more than a week old are best for hard cooking and peeling.

Why is an egg white sometimes cloudy?

Cloudiness of raw white is due to the presence of carbon dioxide, which has not had time to escape.

Why do some hard-cooked eggs have a greenish ring around the yolk?

The harmless greenish ring is due to an iron and sulphur compound, which forms when eggs are overcooked or not cooled quickly.

What are the stringy white pieces in egg whites?

These edible rope-like strands of egg white, called chalazae (ka-LAY-zee) keep the yolk centred in the thick white.

Are eggs an economical food?

Eggs are one of today’s best value food buys. Eggs supply all natural high-quality protein and a variety of important vitamins and minerals* at a very low price. See how egg prices compare with other animal protein foods on a ‘per gram of protein’ basis.